1. Field of the Invention
This invention refers to a mechanism, which may possibly be embodied in the form of a cartridge, for a mixing valve of the so-called sequential type.
2. Description of the Prior Art
The so-called "sequential" mixing valves are those in which a single control member is movable with a sole degree of freedom and, during a complete stroke, starting from a rest position in which the delivery is shut off, during a first stage allow delivering only cold water, whose delivery rate increases up to a pre-established maximum, then during a second stage (stage of mixing) they effect the mixing of hot water in an increasing ratio with respect to the cold water, up to delivering only hot water, and finally in a third possible stage (which however may be missing) they reduce the delivery rate of the hot water.
These sequential mixing valves have the advantage of requiring, for the operation of regulating the flow, only the displacement, in the opposite ways of the same direction, of the single control member, which may be a long lever. As a consequence, their control is very easy and it may be effected without difficulty by disable persons too. For this reason the sequential mixing valves are preferred in the public houses, and according to some regulations they are made compulsory, whereby in certain cases there is the need of replacing the sequential mixing valves for the pre-existing installed single lever mixing valves. In view of the embodiments known up to-day of the sequential mixing valves, in those cases it was necessary to materially replace the whole valve, thus incurring a noticeable cost, because there was no possibility of operating an adjustment thereof to the regulations. Moreover, the known sequential mixing valves have relatively complicated and cumbersome structures, and in any event they do not allow to regulate the maximum delivery rate allowed, as it is often required. This may be done only by using separate control valves inserted upstream or downstream the sequential mixing valve. In the manufacture of such known sequential valves, no important part may be used, that is used for the manufacture of single lever mixing valves too. Thus, no standardization is possible in the manufacture of both types of valves.
A sequential mixing valve may be embodied in the shape of a cartridge intended to be housed in a valve body, or its mechanism may be directly assembled in a valve body.